The goal of the project is to investigate the language disorder and treatment modalities in primary progressive aphasia (PPA). The approach is multidiscipiinary and will include experts in neurology, speech pathology, neuropsychology, electrophysiology and imaging. The methods will include chronometric neurolinguistic investigations, event-related potentials, voxel based morphometry and diffusion tensor imaging. Several reasons justify a research program focusing on PPA. First, PPA constitutes the only adult-onset disease that selectively attacks the language network in the brain. Second, PPA patients suffer from aphasic disturbances that deserve to be characterized more fully, especially since the early stages of the disease are compatible with effective therapeutic interventions. Third, the slow dissolution of language abilities in PPA offers a unique setting, not duplicated by any other aphasic disturbance, for investigating the neurocognitive organization of language. Fourth, the relative scarcity of PPA patients, the temporal progression of the disease, and the wide catchment area needed to recruit a sufficient number of patients create a situation where the integrated work of a multidiscipiinary team is the most efficient way to conduct a research program focusing on this syndrome. The proposal comes from a team of investigators who have worked on PPA for many years and have collaborated extensively. The patients will be recruited from a clinic that is one of the world's most readily recognized referral centers for PPA. The work will use the resources of the Northwestern Alzheimer's Disease Center in a way that will enhance economy of effort.